Structural and optical properties of thick freestanding A1N films prepared by hydride vapor phase epitaxy

摘要

The morphology, structural and optical properties of void-assisted freestanding HVPE-A1N films were investigated by a combination of non-destructive microscopic and spectroscopic techniques. The freestanding approximately 80 nm thick clear film has a wurtzite crystalline structure with remarkable properties around the central film region. The E2(high)-phonon frequency coincides with reported stress-free film phonon frequency. The low temperature luminescence study of the growth and interface sides of the film is consistent with the incorporation of a high concentration of oxygen impurities. These results are promising as the growth method amenable to the production of freestanding stress-free large area substrates for epitaxial growth.